Make sure to only pack the textures you are actually using! Nobody wants to download an extra 10 MB for nothing.

Install by placing the 'materials' and 'models' folders into the 'Steam\SteamApps\common\Team Fortress 2\tf\' folder.
Alternativly, but not recommended imo, you can place them into 'tf\custom\[whatever]\'.

You can use this anywhere you want, just remember that when uploading a map to the workshop you will have to set me as a contributor. (Even if it's just 1%.) This goes for all content made by anybody, as far as i know.